Question

The vapour pressure of solution having 2 grams of solute X (molar mass-32) in 100 grans of CS2 (vapour pressure-854 torr) is 848.9 torr. The molecular formula of the solute is ?
You don't say if the solute is volatile or non-volatile. I assume it is volatile. Since X is used for mole fraction, I will change the unknown compound to Y.
mols Y = 2/32 = ?
mols CS2 = 100/76 = ?
total molsl = ? + ? = ?
Then XCS2 = mols CS2/total mols = ?
X<sub>Y</sub) = mols Y/total mols = ?

The pressure due to CS2 is
pCS2 = XCS2 * PoCS2 = ?
Total Psolution = 848.9
p<sub>Y</sub> = 848.9-pCS2
Finally,
p<sub>Y</sub> = X<sub>y</sub>*P<sup>o</sup><sub>Y</sub>
Solve for Y po (vapor pressure Y). look it up in tables to find the compound. Post your work if you get stuck.

Related Questions

the vapour pressure of a solution having 2g of solute X ( molar mass=32)in 100g of CS2(vapour pressu... Find molality of a solution containing non - volatile solute if its vapour pressure is 2% below the... the vapour pressure of 2.1%solution of non electrolyte in water at 100 degree celsius is 755 mm Hg.c... When 3.15 g of a nonelectrolyte solute is dissolved in water to make 135 mL of solution at 21 °C, th...